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In this paper, we constructed a traveling wave solutions expressed by three types of functions, which are hyperbolic, trigonometric, and rational functions. By using a fractional sub-equation method for some space-time fractional nonlinear partial differential equations (FNPDE), which are considered models for different phenomena in natural and social sciences fields like engineering, physics, geology, etc. This method is a very effective and easy to investigate exact traveling wave solutions to FNPDE with the aid of the modified Riemann–Liouville derivative.

Specific features of silicon carbide layer formation with the structure (polytype) different from the SiC-substrate structure (polytype) are considered. Simple theoretical foundations of the nonstoichiometric character, impurities, C- and Si-faces effect on the heteropolytype epitaxy (HPE) of silicon carbide are proposed. By means of Harrison’s bond orbital model it is shown that the adsorption possibility for the C-face is much greater than for the Si-face. Within the scopes of the earlier proposed models (D-model and vacancy model) it is demonstrated that the presence of impurities changes characteristic lifetimes of the HPE process and the transition layer widths: impurities which enforce the interpolytype transition decrease corresponding life-time constants and the transition layer widths. For interpretation of the polytype stripes existence within the transition layer, the model of specific spinodal decomposition taking into account vacancy concentrations variations in both SiC sublattices is used.

In age-hardenable Cu–Ti alloys, cold work before aging enhances their mechanical properties and shortens the aging time for obtaining the maximum hardness. In order to discuss hardening behaviors, microstructural evolutions such as dislocation rearrangements, progress of spinodal decomposition, and subsequent precipitation from the spinodal region during aging need to be analyzed precisely. Therefore, we employed a probing method combining the small- and the wide-angle X-ray scattering methods to characterize the precipitate size and the progress of spinodal decomposition, respectively. Sideband peaks appearing adjacent to Bragg reflection peaks in the X-ray diffraction patterns of a copper matrix were analyzed to estimate the development of compositional modulations of titanium accompanied by spinodal decomposition. The results of these analytical procedures revealed that the growth rates of the spinodal region and nanometer-scales precipitates in Cu–Ti alloys are less susceptible to dislocations introduced during cold working before aging, and that dislocations introduced during prior cold working annihilate in the initial aging stage. Consequently, overaging, which is mainly induced by dislocation annihilation, in a cold-worked Cu–Ti alloy occurs after a shorter aging time than in an unworked alloy.

The phase-field method, coupled with the micro-elastic model and irradiation-induced cascade mixing model, has been employed to investigate the spinodal decomposition in U-Mo and U-Mo-Zr alloys. The microstructure evolution of U-Mo or U-Mo-Zr alloys under different initial conditions, such as the alloy composition, aging temperature and irradiation intensity, were simulated to study the effect of cascade mixing on the miscibility gap, morphology and volume fraction of the decomposed phases. The simulation results demonstrate that irradiation-induced cascade mixing impedes the process of spinodal decomposition, and that irradiation shrinks the composition range of the miscibility gap in the alloys. Irradiation-induced cascade mixing slows down the anisotropic growth rate of the spinodal decomposition, yet this phenomenon can be weakened with increasing aging temperature. Adding an appropriate amount of Zr to a U-Mo alloy can effectively prevent the contraction of the miscibility gap caused by irradiation.

Passive daytime radiative cooling (PDRC) relies on simultaneous reflection of sunlight and radiation toward cold outer space. Current designs of PDRC coatings have demonstrated potential as eco-friendly alternatives to traditional electrical air conditioning (AC). While many features of PDRC have been individually optimized in different studies, for practical impact, it is essential for a system to demonstrate excellence in all essential aspects, like the materials that nature has created. We propose a bioinspired PDRC structure templated by bicontinuous interfacially jammed emulsion gels (bijels) that possesses excellent cooling, thinness, tunability, scalability, and mechanical robustness. The unique bicontinuous disordered structure captures key features of Cyphochilus beetle scales, enabling a thin (130 μm) bijel PDRC coating to achieve high solar reflectance (≳0.97) and high longwave-infrared (LWIR) emissivity (≳0.93), resulting in a subambient temperature drop of ∼5.6 °C under direct sunlight. We further demonstrate switchable cooling inspired by the exoskeleton of the Hercules beetle and mechanical robustness in analogy to spongy bone structures.

Highlights • Microstructural change and phase transformation of each individual layer of the gradient coating are studied. • Thermal stability of the coating is: BL-1 < BL-2 < TL < HEA-NL. • Fe atoms deriving from steel substrate make neighboring Cr-layer transform into σ-phase layer. • Microstructure-property relationship is shown. Abstract A high-performance AlCrTiSiN high-entropy alloy (HEA) nitride coating, consisting of a columnar CrN (BL-1), a nano-multilayered CrN/AlCrN (BL-2), a columnar AlCrN (TL) and a nano-multilayered AlCrTiSiN HEA nitride layer (HEA-NL) towards to surface, was isochronally annealed at 700 °C ∼ 900 °C. Microstructural change and phase transformation of each individual layer of the HEA nitride coating were studied, as well as microstructure-property relationship. Phase transformation sequence of CrN → Cr 2 N → Cr → σ-CrFe occurs in the BL-1 by nucleation and growth upon annealing, whereas the fcc-AlCrN solid solution of the BL-2 adopts a two-step phase transformation sequence: first to enriched-Al and enriched-Cr fcc-domains by interface-directed spinodal decomposition, and subsequently to hcp-AlN and σ-CrFe by recrystallization, accompanied by the dissolution of layered structure and the diffusion of Fe deriving from steel substrate. The TL shows two different features from that of the BL-2: (i) there is a precipitation process of hcp-AlN from the fcc-AlCrN; (ii) the spinodal decomposition is isotropic spinodal decomposition. The HEA-NL shows drastic differences in spinodal decomposition behavior and microstructure compared to the TL, in which interface-directed spinodal decomposition produces a triple-layer consisting of a rich-Cr/Ti layer fcc-domains confined by two enriched-AlN ones, simultaneously resulting in a notable self-hardening. Subsequently recrystallization results in a aging softening at 900 °C due to the dissolution of nano-multilayered structure, the phase transformation of enriched-Al fcc-domain to hcp-AlN and the formation of soft Cr. Moreover, both Cr 2 N and σ-phase layers deteriorate the adhesion strength. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The formation of submicron polystyrene (PS) particles based on dewetting process during spin-coating was investigated. The surface morphologies on glass substrates were analyzed. The formation of particles was achieved using PS with relatively high molecular weight (Mw ≥ 3250). In addition, it was observed that the particle formation proceeded through sequential morphological changes in the order of initial wet thin film, secondary spinodal-decomposed structures, and eventual dewetted particles. One of the fabricated samples exhibited obvious optical resonance in the visible region based on the relationship between particle dimeters and optical wavelengths in the visible region. The optical resonance strongly depended on the ambient refractive index, which can be used for optical sensor-chips. Finally, a multi-functional biosensor-chip was demonstrated to detect glucose in water solutions. [ABSTRACT FROM AUTHOR]

In this study, we report about the occurrence of phase separation through spinodal decomposition (SD) in spinel manganese ferrite (Mn ferrite) thin films grown by Dynamic Aurora pulsed laser deposition. The driving force behind this SD in Mn ferrite films is considered to be an ion-impingement-enhanced diffusion that is induced by the application of magnetic field during film growth. The phase separation to Mn-rich and Fe-rich phases in Mn ferrite films is confirmed from the Bragg's peak splitting and the appearance of the patterned checkerboard-like domain in the surface. In the cross-sectional microstructure analysis, the distribution of Mn and Fe-signals alternately changes along the lateral (x and y) directions, while it is almost homogeneous in the z-direction. The result suggests that columnar-type phase separation occurs by the up-hill diffusion only along the in-plane directions. The propagation of a quasi-sinusoidal compositional wave in the lateral directions is confirmed from spatially resolved chemical composition analysis, which strongly demonstrates the occurrence of phase separation via SD. It is also found that the composition of Mn-rich and Fe-rich phases in phase-separated Mn ferrite thin films deposited at higher growth temperature and in situ magnetic field does not depend on the corresponding average film composition. [ABSTRACT FROM AUTHOR]

We present multilayer formation via spinodal decomposition in rutile TiO 2 -VO 2 (TVO) epitaxial films on sapphire substrates. (001)- and (101)-oriented TVO solid-solution films are grown epitaxially on TiO 2 /Al 2 O 3 using a pulsed laser deposition technique and annealed inside the spinodal region. X-ray diffraction measurements and scanning transmission electron microscopy (STEM) observations show that the films are phase-separated along the [001] direction and lamellar structures are formed in a parallel or slanted direction to the sapphire substrates depending on the film orientation. The results indicate the multilayer formation via spinodal decomposition in the TVO films. STEM investigations also reveal a relatively high Ti concentration in the decomposed phases, reflecting the influence of lattice deformation on the phase decomposition in the films. Our work shows that spinodal decomposition is a promising approach for the formation of a multilayer structure in TVO films and helps deepen understanding the spinodal decomposition in TVO system. [ABSTRACT FROM AUTHOR]

Abstract Spinodal decomposition in the transition metal aluminum nitrides, usually triggered by annealing, can enhance hardness via forming coherent nanometer-size domains, but it is still required to activate during fabrication. Herein, Mo was introduced into Ta-Al-N to obtain Ta-Mo-Al-N films by co-sputtering method, which induced two kinds of phase separations, including ~ 15 at% Mo induced presence of stable wurtzite AlN phase and ~ 28 at% Mo activated spinodal decomposition forming coherent fcc-Ta-Al-N and Mo-Al-N nano-domains. It is found that both hardness and toughness would be worsened by presence of hexagonal wurtzite AlN phase at incorporation of ~ 15 at% Mo. On the contrary, once spinodal decomposition took place at ~ 28 at% Mo, achieving the joint targets of enhanced hardness and toughness, together with reduced friction and improved wear-resistance. It may provide a new strategy to activate spinodal decomposition during fabrication by alloying additional elements. [ABSTRACT FROM AUTHOR]

Fracture surface retains an of the entire deformation history undergone in a material. Hence, it is possible to derive the approximate deformation and fracture properties of a material from a systematic quantitative fractographic analysis when the microstructure is known. In this research, the deformation behaviour and fracture characteristics of a spinodal decomposed copper alloy at various ageing conditions have been investigated thoroughly. Systematic changes in microstructure are implemented in this alloy through the alteration of ageing time at an elevated temperature on different specimens. As a result, the wavelength and amplitude of modulated spinodal structures have been varied, while those of initial inclusion content, other second phase particles' volume/distribution, initial crystallographic texture and grain size were kept unaltered. Spinodal decomposition results from the coherency strains, hence the zone of mismatch of strain/stress between phases/interfaces acts as micro/nano void nucleation sites under tensile deformation. The two-dimensional tensile were correlated with the deformation and fracture properties of the alloy under constant strain rate at different ageing conditions at ambient environment. The results obtained bring fractographic information to the mechanical engineers and nuclear scientists investigating ductile fracture of spinodal decomposed alloys. This is a novel technique to characterise the material from an analysis of the fracture surface features. [ABSTRACT FROM AUTHOR]

Reducing the spatial dimension of ferromagnetic (α 1 ) phase is the most promising route for coercivity enhancement of alnico alloys. It is an experimental fact that the spatial dimension of α 1 phase cannot be reduced below a certain limit (∼25 nm) using conventional processing methods. To obtain finer α 1 phase we have fabricated alnico ribbons with nominal composition of 32.2Fe-36Co-13.5Ni-7.6Al-6.2Ti-3.8Cu-0.5Zr-0.2B by melt spinning and subsequent heat treatments. Very fine Fe-Co rich (α 1 ) rods of the order of 5 nm diameter and 100 nm length embedded in Al-Ni rich matrix are obtained. After simplified heat treatment the properties of the isotropic ribbons are H cj  = 770 Oe, B r  = 6.5 kGs and (BH) max  = 1.86 MGOe. It is shown that alnico ribbons have unprecedented thermal stability described in terms of temperature coefficient of remanence (α) and temperature coefficient of coercivity (β) by measuring magnetic properties at high temperatures (∼800 K). The microstructures of the alloys have been analyzed by Optical Microscope, Scanning Electron Microscope and Transmission Electron Microscope. The phase transition temperatures have been observed by DTA and magnetic properties are measured by PPMS. [ABSTRACT FROM AUTHOR]

Abstract Violent explosive volcanic eruptions are destructive and threaten millions of people and infrastructure. Ejected ash, pumice and gases are end-products of volcanic factories sourced deep within magma chambers and conduits. The different production stages are not directly observable. However, experimental simulation reveals different stages of dynamic volcanic processes. The starting point of explosive volcanic eruptions is determined by the phase separation of an H 2 O fluid from a supersaturated hydrous silicate melt. The number of formed H 2 O fluid vesicles per unit volume of silicate melt (VND) is a basic property that controls the efficiency of fluid-melt separation, ascent velocity and finally explosive volcanism. We performed decompression experiments at superliquidus temperatures to simulate phase separation of a single phase hydrous silicate melt during ascent with AD79 Vesuvius white pumice composition using decompression rates of 0.024–1.7 MPa⋅s−1. The white pumice buried Herculaneum and Pompeii and is representative of other catastrophic phonolitic and trachytic explosive eruptions like the violent 39 ka Campi Flegrei and the 1815 AD Tambora eruption. Here we report a high log ⁡ VND of 5.2 (in mm−3) that is independent from decompression rate within the investigated range. Even at a decompression rate of 0.024 MPa⋅s−1 the formation of a high VND inevitably causes rapid degassing due to short H 2 O diffusion distances from the melt into fluid vesicles. A decompression rate meter based on nucleation theory, which is commonly used to estimate magma ascent velocity during volcanic eruptions using VND of volcanic ejecta, cannot be adapted to explain our experimentally determined decompression rate independent VND. Alternatively, decompression induced H 2 O–silicate melt phase separation may be described by diffusion controlled spinodal decomposition where maximum supersaturation is reached. This process occurs spontaneously and free of activation energy if hydrous melt is driven into thermodynamic instability where the second derivative of free energy of mixing to the H 2 O content is ≤0. However, the decompression rate independent VND has profound consequences for the dynamics of natural polyphase hydrous magma phase separation. Even at low ascent rates spontaneous hydrous melt phase separation facilitates rapid density decrease accompanied by sudden increase of magma buoyancy triggering explosive eruptions. Highlights • High VND of 1.6 × 10 5 mm − 3 in hydrous Vesuvius melt even at low decompression rates. • Decompression rate independent VND in decompressed hydrous Vesuvius melt. • Decompression rate independent VND can be explained by spinodal decomposition. • Decomposition horizon at certain depth is defined by H 2 O content of phonolitic melt. [ABSTRACT FROM AUTHOR]

Abstract Cast austenitic stainless steels (CASS) are excellent alloys because they combine high corrosion resistance with high strength and toughness. However, they are susceptible to embrittlement upon long-term thermal aging at elevated temperatures. Thus, the microstructural evolution pathways during thermal aging need to be understood to predict and potentially prevent embrittlement. Atom probe tomography was used to identify and quantify the microstructural evolution pathways of the δ-ferrite in different CASS alloys aged for up to 10,000 h at temperatures between 290 °C and 400 °C. The four steels – CF8, CF8M, CF3, and CF3M − which vary by Mo and C concentration, each experienced spinodal decomposition of the δ-ferrite, and precipitation of G-phase clusters and Cu clusters attached to the G-phase. There were large differences in the extent of these features due to their Mo and C concentration. Using radial distribution function analysis, the interactions of constituent elements was found to determine the evolution of these features, with Mo and C specifically influencing the movement of Cr, Ni, Si, Mn, and Cu atoms due to their relative miscibility with these elements. The results will help inform predictive models for the use of duplex stainless steels for extended operation at high temperatures. Graphical abstract Image 1 Highlights • Microstructural changes are co-dependent in ferrite. • G-phase precipitation depends on spinodal decomposition due to necessity for heterogeneous precipitation at interface. • Copper clustering depends on amount of G-phase precipitation as they co-precipitate out of G-phase. • Molybdenum enhances spinodal decomposition, G-phase precipitation, and copper clustering. • Carbon, particularly in the absence of molybdenum, limits the amount of G-phase precipitation and copper clustering. [ABSTRACT FROM AUTHOR]

Abstract Lithium iron phosphate (LiFePO 4) is the prototypical two-phase battery material whose complex patterns of lithium ion intercalation provide a testing ground for theories of electrochemical thermodynamics. Using a depth-averaged (a-b plane) phase-field model of coherent phase separation driven by Faradaic reactions, we reconcile conflicting experimental observations of diamond-like phase patterns in micron-sized platelets with observations of surface-controlled patterns in nanoparticles. Elastic analysis predicts this morphological transition for particles whose a-axis dimension exceeds twice the bulk elastic stripe period. We also simulate a rich variety of non-equilibrium patterns, influenced by size-dependent spinodal points and electro-autocatalytic control of thermodynamic stability. Highlights • A simple theory is proposed to explain the size dependence of phase separation patterns in Li-ion battery materials. • Surface controlled patterns arise in nanoparticles due to concentration-dependent surface energy and autocatalytic insertion. • Complex phase patterns arise in micron-sized particles due to anisotropic bulk elastic coherency strain. • Phase-field simulations predict the full variety of experimentally observed phase morphologies. [ABSTRACT FROM AUTHOR]

The effects of thermal aging on microstructure and mechanical property change of δ-ferrite in an austenitic stainless steel weld were investigated. After thermal aging at 400 °C for 20,000 h, spinodal decomposition and G phase precipitation were observed, along with ~80% increase in yield strength measured by nanopillar compression test. Subsequent reversion heat treatment removed spinodal decomposition while leaving G phase, resulting in partial recovery of hardening in δ-ferrite. It was estimated that ~60% of the hardening in the δ-ferrite of the aged specimen was attributed to spinodal decomposition and ~40% to G phase, respectively. [ABSTRACT FROM AUTHOR]

Highlights • Τhree areas of research in nonlinear science are considered that G. Maugin defined in collaboration with the third author. • Necking in cold drawing, spinodal decomposition in diffusive phase transformations and energy transfer in neuronal microtubules. • In all three the common ingredient is the introduction of higher order gradients of deformation in a variational formalism. Abstract This is a modest contribution in memory of Gérard Maugin-a contemporary French scholar of Paris who inspired many young scientists in Greece and maintained special ties with Aristotle University and Thessaloniki. It introduces three particular areas of research in nonlinear science that he defined in collaboration with the third author and presents preliminary one-dimensional results mainly due to previous work of the first author. These pertain to the phenomena of necking in cold drawing, spinodal decomposition in diffusive phase transformations and energy transfer in neuronal microtubules. The common ingredient in all three is the introduction of higher order gradients of deformation in a variational formalism, in order to describe solitary waves and pattern formation that emerge from uniform states when the system enters its nonconvex free energy regime. [ABSTRACT FROM AUTHOR]

Abstract Hindered phenols have been reported effective to remarkably enhance the damping property of acrylic polymers. In this work, the long–term stability of these novel damping materials were investigated on the basis of thermodynamic phase diagrams. The Flory–Huggins interaction parameter χ between different small molecules and poly(butyl methacrylate) (PBMA) were determined through the melting point depression method proposed by Nishi and Wang. The calculated phase diagram curves agreed well with small-angle light scattering, wide-angle X-ray diffraction, and optical transparency measurements. χ gradually decreased to a negative value as temperature increased and the phase diagrams exhbited an upper critical solution temperature-type spinodal curve. The mixtures with the small-molecule loading of less than 28 vol% were found miscibile at temperatures near the glass-transition temperature. Increasing the intermolecular hydrogen bonding strength between the phenol and carbonyl groups of PBMA could effectively reduce the χ value. Meanwhile, increasing the steric hindrance of the phenolic hydroxyl groups and the sizes of small molecules may sufficiently weaken intramolecular hydrogen bonding interactions. These effects suppress the self-aggregation of small molecules and improve the long-term stability of the damping materials. Graphical abstract The upper critical solution temperature-type thermodynamic phase diagrams of acrylic polymer/hindered phenols damping materials were drawn to investigate its'long–term stability. We report that increasing the intermolecular hydrogen bonding strength between the hindered phenol and carbonyl groups of PBMA could effectively reduce the Flory–Huggins interaction parameter χ. Meanwhile, increasing the steric hindrance of the phenolic hydroxyl groups and the sizes of small molecules may sufficiently weaken intramolecular hydrogen bonding interactions. These effects suppress the self-aggregation of small molecules and improve the long-term stability. The phase diagrams are essential not only for the structural optimization of small molecules, but also for determining the composition ratio of these novel damping materials. Image 1 Highlights • The F-H interaction parameter between hindered phenol and acrylic resin was obtained by melting point depression method. • The phase diagrams of small molecule/macromolecule damping materials were constructed. • The effect of intra-/inter-molecular hydrogen bonding strength on the interaction parameters were discussed. • Principles for the structural optimization of small molecules were provided. • The method to determine the composition of the mixture to ensure long-term stability were provided. [ABSTRACT FROM AUTHOR]

A thermodynamically consistent model of strain gradient elastodiffusion is developed. Its formulation is based on the enhancement of a robust theory of gradient elasticity, known as GRADELA, to account for a Cahn-Hilliard type of diffusion. Linear stability analysis is employed to determine the influence of concentration and strain gradients on the spinodal decomposition. For finite domains, spherically symmetric conditions are considered, and size effects on spinodal and miscibility gaps are discussed. The theoretical predictions are in agreement with the experimental trends, i.e., both gaps shrink as the grain diameter decreases and they are completely eliminated for crystals smaller than a critical size. [ABSTRACT FROM AUTHOR]

This paper presents a method of calculating and estimating the composition of starting mixtures for metasilicate glass-ceramics of a new class: Sikams. The method relies on crystal-chemical principles and takes into account isovalent and heterovalent isomorphism under directional solidification conditions. It ensures a high crystallization rate, a desired degree of structural and chemical homogeneity, and optimal physicochemical properties of the material, in which the crystalline component consists of pyroxene solid solutions. Moreover, it simplifies the fabrication process and reduces energy consumption. [ABSTRACT FROM AUTHOR]

In this study, the phase-field method was used to simulate the spinodal decomposition of the β phase in Ti–23Nb– X O (atomic percent (at.%)) alloys ( X  = 1, 2, 3, 4, and 5) at 1073 K and the subsequent stress-induced β → α” martensitic transformation (MT) at 300 K. At 1073 K, the β phase separates into an O-rich β 1 phase and an O-lean β 2 phase in some Ti–23Nb– X O alloys ( X  = 2, 3, 4, and 5). The tendency toward phase decomposition increases with an increase in oxygen content. When an external tensile stress of 240–270 MPa is applied to certain Ti–23Nb– X O alloys ( X  = 1, 2, and 3) along the [0 1 1] β direction at 300 K, a stress-induced β → α” MT occurs. In Ti–23Nb– X O alloys ( X  = 4 and 5), the β 1  → α” MT first occurs at 50–110 MPa and the nanoscale α” phase with a size of around 2 nm is formed, reflecting the (β 1  + β 2 ) microstructure. This change is followed by a β 2  → α” MT at 660 MPa in Ti–23Nb–4O alloy; however, the β 2  → α” MT does not occur even with an external tensile stress of 800 MPa applied along the [0 1 1] β direction in Ti–23Nb–5O alloy. Further, the calculated hysteresis loop of the stress–strain (S–S) curve at 300 K becomes slim as the oxygen content increases. It is therefore concluded that the S–S characteristics of Ti–Nb–O alloys are strongly influenced by the (β 1  + β 2 ) microstructure, which gives rise to a nanoscale heterogeneity of the driving force for the β → α” MT. [ABSTRACT FROM AUTHOR]

Alnico is a prime example of a finely tuned nanostructure whose magnetic properties are intimately connected to magnetic annealing (MA) during spinodal transformation and subsequent lower temperature annealing (draw) cycles. Using a combination of transmission electron microscopy and atom probe tomography, we show how these critical processing steps affect the local composition and nanostructure evolution with impact on magnetic properties. The nearly 2-fold increase of intrinsic coercivity (H ci ) during the draw cycle is not adequately explained by chemical refinement of the spinodal phases. Instead, increased Fe-Co phase (α 1 ) isolation, development of Cu-rich spheres/rods/blades and additional α 1 rod precipitation that occurs during the MA and draw, likely play a key role in H ci enhancement. Chemical ordering of the Al-Ni-phase (α 2 ) and formation of Ni-rich (α 3 ) may also contribute. Unraveling of the subtle effect of these nano-scaled features is crucial to understanding on how to improve shape anisotropy in alnico magnets. [ABSTRACT FROM AUTHOR]

Abstract: The effect of finite grain size on the formation of grain boundary segregations, and on the morphology of precipitates during decomposition, is studied. It is shown that in dilute solid solutions there are critical grain sizes at which decomposition is suppressed, both at the grain boundaries and in the bulk. A generalized phase-equilibrium diagram is constructed that considers the size factor, and a classification of the morphologies of precipitates during grain-boundary decomposition is suggested. [ABSTRACT FROM AUTHOR]

An investigation on mechanical property and electrochemical behavior of the cladding materials aged at 400 °C for different times was carried out by small punch test (SPT) and double loop electrochemical potentiokinetic reactivation (DL-EPR) test. The results showed that thermal aging contributed to spinodal decomposition and G-phase formation in the aged ferrite phase, as well as increase of nano-hardness of ferrite phase. The SP energy by the small punch tests decreased with increase of thermal aging time, which was related to the lattice distortions in G-phase and aged ferrite phase and their interactions with dislocations during deformation process. Thermal aging promoted corrosion and intergranular corrosion susceptibility of the cladding materials. Combined effects of G-phase and spinodal decomposition lowered intergranular corrosion resistance of the cladding material. [ABSTRACT FROM AUTHOR]

In a Mg-9Al alloy containing O atoms (Mg-O-9Al alloy) supplied from the decomposition of TiO 2 nanoparticles in a Mg-9Al melt, the O atoms are mostly located in the eutectic β-phase after solidification. During homogenization treatment, the β-phase decomposes and the α′′-phase (hard) surrounded by thick α′-phase (soft) gradually develops by the spinodal decomposition of the homogenized α-phase. That is, when the compositions of both Al and O atoms are reached at near 5 at% in the α-phase, the spinodal decomposition activates in the range of the homogenization temperatures. The core-mantle structured (i.e., reticular-structured) Mg-O-9Al alloy shows high hardness and elastic modulus, and yield stress of 129 MPa and elongation to failure of 15.7%, much higher than those obtained in the homogenized Mg-9Al alloy (87 MPa and 8.7%). Because the hard α′′-phase is wrapped by the soft α′-phase, the α′′-phase undergoes phase boundary sliding during plastic deformation at room and high temperatures, exhibiting the α′′-phase rotation and shear deformation of the α′-phase. The alloy shows a strain rate sensitivity in the range of 0 (dislocation activity) to 1 (diffusion flow), depending on the plastic deformation mechanism of the α′-phase. [ABSTRACT FROM AUTHOR]

This paper is a preliminary study on the merits of using duplex stainless steel (DSS) as concrete reinforcements. It looks into the post-fire mechanical and corrosion properties of the wrought DSS 2205 after annealing at 500 °C, and compare them with those of an ordinary rebar steel. Spinodal decomposition of the ferrite phase strengthens and embrittles the 2205 DSS. For the rebar steel, however, softening occurs. Even after the 2205 DSS is exposed to 500 °C for 1 week, its ductility as indicated by fracture strain is still comparable to that of the unannealed rebar steel. The present data show that after short-term exposure to temperatures under 500 °C, the ductility and retention of strength of the 2205 DSS are better than those of the the rebar steel. The corrosion performance of the 2205 DSS, both in 3.5% NaCl and in 3.5% NaCl + Ca(OH) 2 , is also better than that of the unannealed rebar steel even if the former is exposed to 500 °C for 1 week. [ABSTRACT FROM AUTHOR]

Vacuum arc melting was used to produce buttons of Al 2.2 CrCuFeNi 2 HEA. High resolution scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) capabilities as well as X-ray diffraction (XRD) were used for microstructural characterization. The alloy solidified dendritically with rosette structure of dendritic core (DC) regions composed of at least 3 concentric circles or semicircles with different phases and morphology. First to solidify was found to be a supersaturated solid solution with matrix B2 structure that underwent spinodal decomposition as the alloy cooled during solidification. The B2, matrix which initially contained nanosize cubical disordered BCC precipitates, later changed to nanosize rectangles (2nd circle), and eventually to micron-size elongated non-faceted precipitates. This was followed by the solidification of the residual Cu-rich liquid in the interdendritic (ID) regions, which separated into two liquids (LPS) upon rejection of more solute into the liquid. We term this liquid phase separation as “constitutional LPS” in contrast with thermal LPS that takes place during cooling of stable or metastable monotectic alloys. Nevertheless, the constitutional LPS was not predicted using the existing thermodynamic databases. [ABSTRACT FROM AUTHOR]